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While more intense convection has been slow to develop in southeastern, the LightningCast probability for >10fl started to increase as synoptic forcing improved. About 13 minutes later (image below), the GLM flash extent density increased to around 30 flashes per 5 minutes, which was well signaled by LightningCast. While the probability depicted by LightningCast wasn’t terribly high (to around 15 percent initially), the upward trend in probability did signal the potential.
-Joaq
Storms off the the west in New Mexico approaching our DSS location in far NW Texas were a great way to test the LightningCast and the associated LightningCast Dashboard. Our DSS location was focused on the “Rita Fire” that was along Hwy 385 between Dalhart, TX and Boise City, OK and partners wanted notice of a 50% probability of lightning within one hour within a 25 nm radius around the fire. Convection was ongoing across NE New Mexico one storm showing deviant motion. This storm was warned on at 2043Z for 1.5″ hail and winds of 60 mph based primarily on radar; however, Octane was being used to monitor the storm as it tracked southeastwards towards the CWA boundary. Octane showed consistent divergent signatures in the direction product and good speed decreases on the upshear side of the updraft before being contaminated by an anvil from another storm to the southwest.
While it was nice that the LightningCast Dashboard allows you to choose different time ranges and an auto refresh rate per a drop-down, I think some other options might be more helpful for support of an event. To help provide a head’s up to partners, it would be valuable to have an option to input a specified area that you would like to be alerted for…with the option of inputting those criteria. For example, being able to have a range ring or being able to draw a polygon for the area of interest and then inputting lightning criteria in there to alert you when those values are reached within your range ring or polygon. The criteria provided for the Rita Fire of 50% probability within the range ring would have alerted us on the Dashboard that the threshold had been reached. As far as the LightningCast product overall…it was an excellent resource for monitoring then alerting the Rita Fire partners once their criteria had been reached. A quick screen grab can be sent to partners as well to indicate where the greatest lightning threat probabilities are located.
– Vera Mae
Protect the Quartet!
Today we were charged with the noble task of watching over the the Quartet Festival located in Lawrenceburg TN. Gaps in the cloud coverage allowed us to utilize some of the satellite products a little more efficiently today. Our first sign of trouble came as convection began to form out in front of the main line moving WNW out of Alabama. LightningCast 60-min prob gave us our first initial heads up that lightning was possible with storms forming out ahead of the main line. A combination of Octane overlaid with GLM data was the primary source in our decision making to issue a notification to the event organizers. Thanks to our quick decision making, everyone is alive to sing again another day.
We combined lightning cast and ENTLN data with the radar to provide ground truth on when lighting was first scene within the 15 mile range ring which allowed us to issue follow up messages regarding the likelihood of ongoing lightning potential. Requesting a LightningCast point too also gave us confidence in issuing notifications to the event organizers.
Discussing the LightningCast Probability data with Kilometers we were discussing ways to get more information out of it. We settled on loading the LightningCast as an image rather than contours. This combined with the sample tool and overlayed with Total Lightning products was more useful when forecasting for a specific DSS point. We also went ahead and limited the data being showed on the lower end of the GLM Flash Density. We didn’t want to exclude the Flash Density on the lowest end all together, but we wanted to highlight and compare the GLM Flash Density to the areas with the highest Octane SpeedSandwich. Our end result was this GIF below:
Today was a day to dive into GLM and Lightning probabilities. Once we settled on what we wanted to look at to make DSS related decisions, we realized that it wasn’t intuitive to the public. We needed a way to redesign the the Lightning Cast data to be easy to look at to the public. Because the NWS already has a color table for threats utilized by our National Centers, we decided to model our threat level based on the SPC’s convective outlook to create new colors for the contours. The following graphic is the end product of that:
As the system moved past, identifying areas that we could issue the all clear on was our next priority. The LightningCast created a nice looking bell curve that lined up with the time that the MCS moved over the event and showed the trends of the storm began to wind down.
Charmander and Kilometers were watching over an event in central Tennessee and employed the lightning cast meteogram. The probability of lightning tool worked (img. 1) great for alerting the event staff to an increase in the lightning threat, providing about 45 minutes of lead time.
I began to monitor the cell for further intensification and any chance that it could become severe. In the background of this work I was also monitoring for lightning activity from the cell. Eventually, the cell did produce lightning. Image two showed the ENTLN product pick up on a series of cloud flashes, with the GLM product showing some light lightning activity two minutes later (img. 3).
Positive for GLM was that the latency was not an issue. What was more of an issue was that the meteogram from lightning cast never plotted the GLM data on the meteogram. If the person working the event shared the meteogram to event organizers, they would assume this was a missed event. Positive though, is that the organizers could be shown the GLM image or ground network data and be assured that their actions were not for nothing. This left us wondering why the meteogram did not show the lightning activity picked up in the vicinity?
We saw that the GLM began showing up when the main line of convection moved through the event space about an hour later than we identified it through alternate means (img. 4).
Image one: Meteogram for the Probability of Lightning product with GLM flash Density.
Image three: GLM Data quality (upper-left), GLM Background Image (upper-right), Day cloud phase RBG overlaid with GLM Flas Density (Bottom-right), ENTLN observed lighting flashes and cloud-to-ground strikes (bottom-right).
Image four: Meteogram for the Probability of Lightning product with GLM flash Density beginning at 15:15 local time.
– Kilometers / Charmander
As a QLCS moved through Tennessee and the threat for severe dropped, we were thinking of a way to message the persistent lightning threat that would still be present. We leaned on the Lightning Cast tool to message this threat.
Before we made the image though, the idea came up to re-do the contours such that they better aligned with the style guide the NWS, or SPC more specifically uses (img. 1). Image two shows how we added two contours and realigned the colors to add consistency with other operational areas of the NWS.
Image two: Lightning Cast with a new 5 and 90 percent contour added and colors of the contours aligned with the risk colors used elsewhere in the NWS. In the background is channel 2- Red Visible satellite.
We compared this with the base style from the lightning cast tool and we felt that our updated style better captured our eyes and made it simpler to interpret by us. We also felt that the public would have a better chance of understanding the product if the colors were more consistent.
Hi everyone!
First blog post for the Satellite Convective Applications Experiment – Week 1, let’s go!
The loop below shows an example of this from the Corpus Christi, Texas. Notice the convection moving out of the frame to the northeast is bounded by prob-lightning contours (Gif 1). My desire would be to have these better matched to the storms. Right now, the contours are too nebulous.
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-Kilometers
A moderate risk for severe storms was forecast for the Southern Plains with hail, wind, and tornadoes as significant threats. Storms quickly initiated in southwest Kansas (See Figure 2) and were ongoing when the testbed started at around 19z. Primarily used during warning operations were ProbSevere, LightningCast, and radar. Thrown in for good measure I used OCTANE to aid in storm motion and direction. ProbSevere was helpful in issuing warnings but was vital in assisting in the hail size mentioned in the warning text.
Figure 1: SPC Day 1 Outlook for June 15, 2023.
Figure 2: 2011z showing ProbHail with a MESH of 2.17” provided the confidence to mention 2-inch hail in the text. There were two separate storms that eventually merged later in the afternoon.
Figure 3: storms were beginning to merge and ProvSevere was as well and thus prompted just one warning instead of two.
Figure 4: New warning with ProbSevere now depicting just one storm.
Figure 5: Storms continued to merge and evolved into a wind signature more than a hail producer. Thus the ProbWind had a nice uptick to 68% at 2133z. Before this time it never rose bout 40%.
Figure 6: Once the convection evolved into a linear wind producer, LightningCast became helpful in how far east to extend the polygon. I used the 75% contour and issued a 60-minute warning.
Figure 7: Captured much of the event to show the evolution of convection and ProbSevere.
Figure 8: OCTANE aided in determining the area of cell merger in southern Grant and portions of Stevens Counties.
– Podium
PHS
The surface based CINH at 20z lined up rather well with the satellite imagery showing the slightly more stable clouds over the eastern CWA.
When sampling an image versus contours, the contour sampling has the entire product name in the readout
PHS captured the initial convection just east of AMA well, even though the convection started an hour earlier than PHS indicated. Image on right is PHS SB CAPE and contours are PHS SB CINH. Home is roughly where the storm is located. Satellite image is around 1930z and PHS forecast is 21z when CINH dropped from 80j/kg to 40 j/kg.
PHS did a reasonable job predicting the general storm coverage by 21z from the 16z run.
Toward the end of the exercise, the storm coverage was well captured by the PHS 16z run. Should have taken this into account for my public graphics when describing the storm evolution.
NUCAPS
This is a NUCAPS sounding in the TX panhandle near AMA vs. a RAP40 sounding at the same point. The RAP has the same trend in the dew point profile as NUCAPS, but is lower.
Noticed the NUCAPS sounding didn’t have the lower dew points around 400 mb as shown in the special sounding. NUCAPS did have a hint of the weak cap near the surface though.
NUCAPS 700-500mb lapse rates from the gridded data was a constant 34.17 C/KM across the map.
NUCAPS forecast for ML CAPE was slightly less than what SPC mesoanalysis had at the same time of 20z.
NUCAPS ML CINH was higher than SPC Mesanalysis for 20z, with some parts of the CWA having almost 90j/kg of CINH south of Liberal, KS.
The 700-500mb lapse rates matched well with SPC meosanalysis for 20z.
OCTANE
OCTANE showed the cumulus developing along the dry line and warm front well. Can also distinguish which clouds are becoming taller.
OCTANE highlighted where convection was taller, and Lightning Cast started to show probabilities for those same updrafts.
ProbHail
Noticed what could be an above anvil cirrus plume with the storm in question. Prob Hail only had a 35% chance for severe hail at the time.
Prob Tor
Noticed the Prob Tor jumped up depending on what cells it was encompassing. Took three screen shots to denote the trend. Seemed reasonable for it to increase since the end cell was ingesting the dry line at the time the probabilities increased.
-Rainman
Today, I took on the role of mesoanalyst during operations. I first looked at PHS fields (mainly MUCAPE and bulk shear) and compared them to the SPC mesoanalysis of said fields. The two agreed well, though I do have a suggestion – PHS bulk shear fields are given in m/s, but knots or mph would be better for quick comparison to SPC mesoanalysis and most model output.
I then looked at OCTANE imagery and immediately took note of the divergence signature associated with an especially robust storm over western DDC (Figure 1). This signature was easy to identify as the environmental winds aloft were relatively light.
Figure 1
As the operational period wore on, LightningCast indicated a high likelihood of convection over the southwest portion of DDC well before any radar returns actually appeared (Figure 2). My group used this information to create a DSS graphic that highlighted this area for likely storm development later (which did in fact end up happening).
Figure 2
OCTANE Direction later captured what at first glance appeared to be a couple divergence signatures over southwestern DDC (Figure 3). Upon closer inspection, however, these signatures were co-located with relative minima in OCTANE Speed. The proximity of these signatures to areas of missing pixels (where winds are likely <5 kts) in OCTANE Direction suggests very light winds and/or lower quality data, per the developer.
Figure 3
– Vort Max
June 15, 2023 – Role playing as DDC, I was tasked with providing DSS for a (fictitious) grass fire near Meade, KS.
DSS: Grass fire near Meade, KS
For this DSS, requested information included lightning within 10 miles of the site, any significant changes in wind speed and direction, as well as other hazardous weather that would pose a risk to emergency personnel containing the fire.
Figure 1.
There was ongoing severe convection within the western half of the CWA by the start of my shift, and there was a high likelihood of this convection approaching the DSS site. As shown in Figure 1, my datasets/tools of choice for tracking severe convection and lightning were as follows: GOES-East Mesosector LightningCast, MRMS Composite Reflectivity, ENTLN intracloud and cloud to ground lightning, surface observations, Time of Arrival Tool, Distance Bearing Tool, and Range Rings Tool.
Ground based lightning observations and LightningCast complimented each other nicely when assessing the potential for lightning at the site. Additionally, LightningCast picked up on additional agitated Cu well ahead of the main line of thunderstorms closer to the DSS Site. Using the Time of Arrival tool to track the main cluster of cloud to ground lightning associated with the severe convection was also very useful in providing information on potential to see most lightning via advection, in the absence of additional convective initiation and/or a rapid change in forward speed in ongoing convection.
Figure 2.
Some consideration was made to not “overwarn” on lightning potential as the main breadth of lightning would likely come from the severe convection still well off to the west. So with this particular scenario, I set an internal threshold of 80% within LightningCast to send a DSS message. The data readout of the parallax corrected LightningCast offered within AWIPS (not shown) was favored over the non-parallax corrected time series (Figure 2), giving higher confidence in the true probability of occurrence used within the DSS message. This gave around a 35 minute lead time before the first strike was detected within 10 miles of the DSS site. Had we used the non-parallax corrected readout values, lead time would have been much shorter, around 10 minutes using 1-minute imagery and less than 10 minutes using 5-minute imagery. This clearly demonstrates the value of using parallax corrected data compared to non-parallax corrected data when performing DSS.
Here was the DSS message sent at around 21:10 UTC:
Severe thunderstorms have developed around 50 miles to your west, and will likely move over your site between 5:15 pm to 6:30 pm CDT. There is a high chance for storms to remain severe by the time they reach your site, bringing very strong winds over 70 mph out of a direction ranging between northerly to westerly, large hail, heavy rainfall, frequent lightning. We still cannot rule out the potential for a brief tornado, although the chance for a tornado is much lower than previous hazards mentioned. Because of the approaching thunderstorms, the chance for lightning to occur within 10 miles of your site within the next hour (5:15 pm CDT) is over 80%.
– 0SMBLSN
